Computer Networks Multiple Choice Questions on “Packet Switching & Circuit Switching”.
1. A local telephone network is an example of a _______ network.
a) Packet switched
b) Circuit switched
c) Bit switched
d) Line switched
Answer: b
Clarification: Circuit switching is connection oriented switching technique, whereas in the case of packet switching, it is connectionless. Circuit switching is implemented in the Physical layer, whereas packet switching is implemented in the Network layer. Internet too is based on the concept of circuit switching.
2. Most packet switches use this principle ____________
a) Stop and wait
b) Store and forward
c) Store and wait
d) Stop and forward
Answer: b
Clarification: The packet switch will not transmit the first bit to outbound link until it receives the entire packet. If the entire packet is not received and the time-out period expires, the packet switch will inform the sender to resend the part of packet or the entire packet based on the algorithm being used.
3. If there are N routers from source to destination, the total end to end delay in sending packet P(L-> number of bits in the packet R-> transmission rate) is equal to ______________
a) N
b) (N*L)/R
c) (2N*L)/R
d) L/R
Answer: b
Clarification: The equation to find the end to end delay when no. of bits, transmission rate and no. of routers is given by (N*L)/R. The total end to end delay, that is, nodal delay is the sum of all, the processing delay, queuing delay, transmission delay and propagation delay.
4. What are the Methods to move data through a network of links and switches?
a) Packet switching and Line switching
b) Circuit switching and Line switching
c) Line switching and bit switching
d) Packet switching and Circuit switching
Answer: d
Clarification: Packet switching and Circuit switching are two different types of switching methods used to connect the multiple communicating devices with one another. Packet switching is used in conventional LAN systems and circuit switching is used in telephonic systems.
5. The required resources for communication between end systems are reserved for the duration of the session between end systems in ________ method.
a) Packet switching
b) Circuit switching
c) Line switching
d) Frequency switching
Answer: b
Clarification: In circuit switching, a physical path between the sender and receiver is established. This path is maintained until the connection is needed. Circuit switching is implemented in the Physical layer and is used in telephonic systems.
6. As the resources are reserved between two communicating end systems in circuit switching, ___________ is achieved.
a) authentication
b) guaranteed constant rate
c) reliability
d) store and forward
Answer: b
Clarification: Circuit switching is connection oriented and is always implemented in the physical layer. Once a path is set, all transmission occurs through the same path. It is used since the early times in telephonic systems.
7. In _________ systems, resources are allocated on demand.
a) packet switching
b) circuit switching
c) line switching
d) frequency switching
Answer: a
Clarification: In packet switching, the bits are received in out of order and need to be assembled at the receiver end, whereas in the case of Circuit switching, all the bits are received in order. All transmissions may not occur through the same path in case of packet switching.
8. Which of the following is not an application layer service?
a) Network virtual terminal
b) File transfer, access, and management
c) Mail service
d) Error control
Answer: d
Clarification: Application layer is the topmost layer in the OSI model. Network virtual terminal, mail service, file transfer, access and management are all services of the application layer. It uses protocols like HTTP, FTP, and DNS etc. to provide these services.